The invention relates to a tuning circuit with automatic wave range change-over, comprising a wave range change-over circuit and a setting circuit for generating a setting signal for consecutively tuning over a number of wave ranges, a threshold circuit to which the said setting signal is applied and from which a d.c. voltage signal which depends on the setting of the tuning is obtained, this d.c. voltage signal having a value which is constant over that wave range and being switchable for each wave range by means of the threshold circuit.
German Patent Specification No. 2,412,689 discloses a tuning circuit of the above-mentioned type wherein there is applied to a tuning diode the tuning signal and also the d.c. voltage signal via a wave range change-over diode and a coil-resistance network. Such a tuning circuit has the advantage that it can scan all wave ranges in one searching action, which is particularly attractive for automatic search tuning circuits. A disadvantage is, however, that a tuning unit to be used in the circuit must be of a special construction which is adapted to the circuit.